about simirality component (threshold)...

Replies to This Discussion

Permalink Reply by David Rutten on July 26, 2013 at 8:12am

Similarity tests whether two numeric values are identical within a relative tolerance. So instead of testing to within an absolute tolerance:

A - B < t

The equation instead is:

(|A - B| < t*A) & (|A - B| < t*B)

Or, in English:

If the Absolute difference between A and B is less than T% of either A or B, then the two values are considered similar.

So let's do a few examples:

A = 100.2

B = 99.7

T = 1%

The absolute difference between A and B = 0.5

One percent of A = 1.002 and one percent of B = 0.997

Since 0.5 is larger smaller than either of those percentages, A and B are considered to be similar.

A = 0.65

B = 0.67

T = 0.5%

The absolute difference between A and B = 0.02

Half a percent of A = 0.00325 and half a percent of B = 0.00335

Since 0.02 is larger then either of the percentages, A and B are considered to be different.

--

David Rutten

david@mcneel.com

Tirol, Austria

Permalink Reply by Joongha Park on July 27, 2013 at 12:32am

Thank you for your answer to simirality component.
There is a thing to be worried about. I have heard simirality component is to be based on a number.
If the input-number becomes the surface, which number is input-number, area or length or another number ?????
I want to know what makes the input-number.

plz tell me your comment
 

Permalink Reply by David Rutten on July 27, 2013 at 4:27am

Darn, I just realised the number conversions have a major bug. Instead of getting the area of a surface, you get the length of the edge-curves. 

This is what should happen* when you plug non-numeric data into a Number parameter:

1. Boolean.  False→0.0, True→1.0
2. Domain.  The (signed) length of the domain, i.e. T1-T0
3. Domain 2D. The (signed) area of the domain, i.e. V1-V0 * U1-U0
4. Complex.  The Real component of the complex number
5. Text.  The text is evaluated as an expression. The resulting type (number, boolean, text, complex, vector etc.) is then parsed
6. Colour.  The brightness of the colour (Black→0.0, White→1.0)
7. Time.  Number of ticks (1 tick = 100 nanoseconds) since January 1st 1900
8. Vector.  The length of the vector
9. Point.  The distance from the point to (0,0,0)
10. Plane.  The distance from the plane origin to (0,0,0)
11. Curve.  Length of the curve
12. Surface/Brep.  Area of the brep
13. Mesh.  Area of the mesh
14. Box.  Area of the box

* and what will happen again come the next version.

--

David Rutten

david@mcneel.com

Tirol, Austria